1. Technical Field
This invention relates to furnaces for use in melting and molding metals often referred to as casting. More particularly, this invention relates to a casting furnace incorporating a mold insertion and withdrawal system that operates adjacent to the mold and mold support thereby eliminating the need for a pit thereunder housing such a system. Specifically, the invention is a casting furnace with a mold insertion and withdrawal system attached thereto and incorporating an offset mold elevator for moving a mold from a mold loading chamber to a melt processing chamber while eliminating the need for a pit. The system further incorporates a readily removable chill plate on which the mold rides, and an overhead material feed system.
2. Background Information
Casting furnaces are used to melt metals such as chrome alloy, super alloy, titanium, and nickel-based castings or other like materials whereby the molten metals are poured into molds in the shape of the desired end product. This overall process is known as casting. During casting, one of the necessary operations is the insertion of the molds into the furnace prior to use, and the removal of the molds from the furnace after use.
A typical system for performing this process includes a furnace with a melt processing chamber coupled to a mold loading chamber whereby some form of a withdrawal cylinder is positioned directly under a plate or base that supports the mold. The plate is used to lift the mold into and out of the melt-processing chamber of the furnace. The withdrawal cylinder is a cylinder actuated in and out of an elevator tube positioned beneath the lowest point that the plate must actuate to during the use of the mold, whereby this elevator tube is positioned within a furnace pit where it extends into the pit and/or through a hole within the pit and into the ground or foundation on which the furnace sets, or into some form of an area below the furnace.
Although these systems operate generally in the intended manner, certain disadvantages and problems exist. First, the furnace may only be located where a pit or similar chamber beneath the furnace may be provided to house at least the elevator tube. Second, extra costs are incurred to build or modify such a building due to additional foundational costs associated with the pit requirement. Third, a pit is a confined space and thus it is difficult to maintain, improve, fix and/or operate the parts of the withdrawal cylinder and/or furnace positioned therein.
Furthermore, the withdrawal cylinder or elevator tube is very susceptible to major damage in the event of a mold breakout or overflow. This is particularly true since the cylinder is located directly under the mold or in close proximity to the mold whereby molten material during a breakout or overflow contaminates substantially all parts positioned below the mold including the withdrawal cylinder or elevator tube. This contamination often causes significant damage to seals, housings, and other parts as well as requiring significant clean-up of the harden metal thereon or replacement of many parts of the system.
It is also noteworthy that the mold elevator shaft in current systems is typically a hydraulically actuated, precision ground and polished chrome design to satisfy the water cooling requirements. Such a design is expensive.
For these and other reasons, it is thus very desirable to provide an improved mold withdrawal system.